3. Unsatisfactory course despite 3 immunosuppressive agents (usually azathioprine, methotrexate and infliximab, adalimumab and/or certolizumab) in addition to corticosteroids. Patients should have relapsing disease (i.e. 1 exacerbation/year) despite thiopurines, methotrexate and/or infliximab/adalimumab/certolizumab maintenance therapy or clear demonstration of intolerance / toxicity to these drugs.